This invention relates to an atmospheric deaerator unit for use in a boiler feed water system for eliminating non-condensable gases from boiler feedwater. Non condensable gases are principally carried into the feedwater system by the addition of makeup water for compensation of losses during the steam cycle. Additionally, gases can be generated in the steam circuit such as carbon dioxide which is generated from carbonate salts reacting with metallic components in the steam circuit.
The jet spray atmospheric deaerator of this invention is of the type described in my prior U.S. Pat. No. 4,698,076 issued October 6, 1987, entitled ATMOSPHERIC DEAERATOR UNIT, and in my U.S. Pat. No. 3,487,611 issued January 6, 1970, entitled SPRAY-FLOW DEAERATOR. Generally, deaerators are rated as either 0.03 cc/liter or 0.005 cc/liter deaerators. The latter being the most effective in removing desolved gases. In general, to achieve a reduction of dissolved air and gases to 0.005 cc/liter, the deaerator must operate in a pressurized circuit. While the referenced patent entitled ATMOSPHERIC DEAERATOR UNIT, discloses one arrangement for achieving a high performance deaerator at atmospheric pressure, the deaerator of this invention provides an alternate solution for the problem of obtaining a high performance deaerator that is vented to atmosphere. Atmospheric deaerators are preferred for their safety features and their low cost in maintaining vessels at low temperatures.
The deaerator unit of the present invention is constructed with a divided vessel in which one side is steam pressurized to less than 1 psi. This small pressure differential allows for internal deaeration circuits that substantially reduce the venting of any steam without the various temperature controls required in my prior atmospheric deaerator system.